1. Field of the Invention
The present invention relates to fluid administration systems, and more particularly to fluid administration systems having an occluder adapted to prevent fluid free-flow. More specifically, the present invention relates to a one-piece unitary occluder for use with a pump of a fluid administration system which is connected to a tube assembly and adapted to prevent fluid free-flow therethrough.
2. Prior Art
Administering fluid containing medicine or nutrition to a patient is generally well-known in the art. Typically, the fluid is supplied to a patient by a tube assembly which interconnects a fluid source to a patient. The fluid is supplied to the patient through either an enteral connection which accesses a visceral organ (gastrointestinal feeding), or through a parenteral connection which accesses a non-visceral organ (intravenous feeding).
The fluid flow rate through the tube assembly is typically controlled by a mechanical clip which is designed to progressively occlude the tube and selectively impede the fluid flow induced by gravity. One such mechanical clip which operates to occlude a portion of the tube is a conventional roller clamp that has a hollow body with opposed openings and a pair of angled slots opposite one another which are formed transverse to the openings. The clip further includes a wheel having an axle which is coupled to the body with the axle fitted within the slots. The tube is the inserted through the openings and the wheel is rolled along the slots to pinch a portion of the tube against the body which progressively occludes the tube. Although devices of the above-mentioned character operate to provide a cost-efficient method for controlling the flow rate, these devices must be manually actuated. Further, another drawback is that the wheel may be inadvertently bumped or jostled out of position resulting in an inappropriate flow rate.
In order to enhance flow-rate control, calibrated pumps have been found to be useful. One such pump that has been used in the art is a peristaltic pump connected in-line along a portion of the tube between the fluid source and the patient. The pump advances the fluid through the tube by occluding successive portions of the tube and then urging each occluded portion forward. When a pump is utilized to control the flow rate, mechanical clips are typically not employed or are disengaged to prevent the clamp from interfering with the flow rate.
Peristaltic pumps are generally classified as being either a rotary, such as the device described in U.S. Pat. No. 4,913,703 to Pasqualucci et al. entitled xe2x80x9cSafety Interlock System for Medical Fluid Pumpsxe2x80x9d, or linear, such as the device described in U.S. Pat. No. 4,493,706 to Borsangi entitled xe2x80x9cLinear Peristaltic Pumping Apparatus and Disposal Cassette Thereforexe2x80x9d, both of which are incorporated herein by reference. Generally, rotary peristaltic pumps have a motor driver rotor mounted on a surface of the pump which carries two or more circumferentially spaced apart rollers designed to occlude a portion of the tube. As the motor rotates the rotor, the spaced apart rollers are sequentially brought into contact with, and occlude, portions of the tube. A predetermined volume of fluid is contained between each of the occluded portions so that this measured volume of fluid is advanced through the tube.
Rotary peristaltic pumps can be further subclassified as being either clinical, for use with bedridden patients, or ambulatory, for use with patients that have some degree of mobility. The ""703 patent describes a representative clinical pump having a tubing assembly with a pair of members each receivable within a corresponding recess. The tube assembly is engaged with the pump by coupling the first member with the corresponding recess, stretching the tube around the rotor, and then coupling the second member with the other recess. In contrast, ambulatory peristaltic pumps, such as that described in U.S. Pat. No. 5,181,842 granted to Sutherland, et al. entitled xe2x80x9cPeristaltic Infusion Devicexe2x80x9d, include a battery operated pump for use by patients who are capable of some degree of mobility. These peristaltic pumps have a rotor member and a swing arm rotatably mounted adjacent to the rotor. The arm is movable between an open position and a closed position. In the open position, the tube assembly is slack to simplify threading it about the rotor. Then the swing arm is biased into the closed position to automatically align and stretch the tube around the rotor by the arm.
Although clinical and ambulatory peristaltic pumps have substantially improved the art, one drawback found with such devices is that once the tube assembly is disengaged, either intentionally or unintentionally from the pump, the flow rate is unrestrained as the fluid is drawn through the tube due to gravity. This situation is known as fluid free-flow and may present an undesirable, or even life threatening situation, if undetected because of the risk of overfeeding or overmedicating a patient.
In order to overcome the above-noted drawbacks to fluid administration systems utilizing pumps, several devices have been suggested which operate to automatically occlude a portion of the tube and prevent fluid free-flow if the tube becomes disengaged from the pump while also permitting uninhibited fluid flow when the assembly is properly engaged to the pump. For instance, a variety of automatic occluders have been suggested to improve the art such as the device disclosed in U.S. Pat. No. 4,689,043 to Bisha entitled xe2x80x9cIV Tube Activatorxe2x80x9d which describes a clamp for use with a peristaltic pump. The clamp includes a V-shaped channel which is spring biased into a closed position where the narrow portion of the V-shaped channel is sized to substantially crimp, or occlude, a portion of the tube and prevent fluid flow therethrough. The clamp may be urged into an open position by a handle which overlays the pump and depresses the springs such that the tubing is positioned within the wider portion of the V-shaped channel to permit unrestricted flow through the tubing. If the handle is released either intentionally or unintentionally, the V-shaped portion will automatically slide into the closed position and prevent fluid free-flow by crimping or occluding a portion of the tubing assembly.
Another automatic occluder is disclosed in U.S. Pat. No. 5,704,582 to Winterer, et al. entitled xe2x80x9cPinched Clipped Occluder for Infusion Setsxe2x80x9d which describes a clip that is positioned between a housing and a cover of a pump. The clip has a plunger biased by a spring towards a portion of the tube so that the tubing may be occluded. Fluid flow through the tube may only be established when the plunger is biased away from the tube which occurs when the cover is properly coupled with the housing. However, once the cover becomes disengaged from the housing, the plunger is automatically biased into the closed position by the spring to prevent fluid free-flow.
Although both of the aforementioned automatic occluders have advanced the art, both devices are mechanically complex and prone to mechanical failure. In addition, the mechanical complexity also results in occluders which are expensive to manufacture.
Accordingly, one skilled in the art can best appreciate that several advances would be still be desirable. For instance, it would be desirable to have a fluid administration system which has an automatic occluder capable of preventing fluid free-flow through a portion of the tube. In addition, it would also be desirable to have an occluder which has a one-piece unitary design.
In brief summary, the present invention overcomes and substantially alleviates the deficiencies present in the art by providing a one-piece unitary occluder for a fluid administration system which is adapted to prevent fluid free-flow. The one-piece unitary occluder is used in a fluid administration system having a pump connected in-line along a tube assembly.
Generally, the pump includes a body having a pair of shoulders and a recess formed therein. Extending from the body is a rotor while a cover is pivotably attached to the body over the rotor. The tube assembly includes three interconnected tube segments each having a distal end and a proximal end. A fluid source is connected to the distal end of the first tube segment while the proximal end of the first tube segment is connected to the distal end of the second tube segment by a drip chamber having an abutment surface. The proximal end of the second tube segment is interconnected to the distal end of the third tube segment by a coupling having an external flange. Finally, the proximal end of the third tube segment is connected to a patient.
The tube assembly is engaged with the pump by threading the assembly around the rotor with the abutment surface and external flange engaged with the first shoulder and second shoulder, respectively. The abutment surface is spaced apart from external flange by the length of the second tube segment. Preferably, this length permits the abutment surface and the external flange to be properly captured by the first and second shoulders, respectively, while stretching the second tube segment about the rotor. Finally, each of the tube segments have a lumen to allow the passage of fluid therethrough.
One unique aspect of the one-piece unitary occluder is that it is fitted within the recess of the pump. Unlike prior art occluders which include multiple separate elements, the one-piece unitary occluder of the present invention has a generally cylindrical shape formed from a single sheet of material having proximal and distal ends defining first and second openings, respectively, at least partially overlapping one another and an aperture disposed therebetween. Each of the openings and the aperture are sized to receive a portion of the tube assembly therethrough. Adjacent the first opening is a pair of hooks adapted to engage the second opening and maintain the unitary occluder in its generally cylindrical shape with both openings in an aligned configuration relative to the aperture which is located diametrically across from the openings.
The one-piece unitary occluder also includes a V-shaped bend proximate the distal end thereof adapted to spring radially outwardly away from the proximal end once the hooks are released from the second opening so that the occluder is capable of uncoiling and misaligning the first and second openings relative to the aperture. When the occluder uncoils from its generally circular configuration the portion of the tube assembly which extends through the first and second openings and the aperture of the one-piece unitary occluder is occluded to prevent fluid free-flow through the assembly. The one-piece unitary occluder is fitted within the recess of the pump such that a portion of the occluder extends upwardly away from the body. When the cover is pivoted into a closed position, the cover abuts and biases the occluder to disengage the hooks from the second opening while also maintaining the alignment between both opposed openings and the aperture. However, once the cover of the pump is moved into an open position, the occluder springs into the misaligned position with each opening being misaligned relative to the aperture in order to prevent fluid flow through the tube assembly.
To manufacture the occluder of the present invention, a body is cut from a flat sheet or band of suitable metallic material. First and second openings are then punched through the body proximate the distal and proximal ends, respectively, while an aperture is concurrently punched through the body between the first and second openings. After the aperture and openings are punched through the body, a circumferential shoulder is formed about the aperture extending upwardly from the body, while a pair of tabs are formed proximate the first opening and then bent downward from the body to form hooks. The second end portion is bent into a substantially V-shaped configuration. Finally, the body is rolled into a substantially cylindrical shape with the distal end overlaid by the proximal end with the hooks extending outwardly from the body and capturing the second opening as the shoulder extends inwardly.
In operation, the user of the present invention places the one-piece unitary occluder about a portion of the tube assembly such that a portion of the tube assembly is threaded through the aperture and the pair of openings. The abutment surface of the drip chamber is then engaged with the first shoulder and the second tube segment is wrapped about the rotor of the pump. The user then stretches the second tube segment so that the coupling may be engaged with the second shoulder. Finally, the one-piece unitary occluder is fitted into the recess such that a portion of the occluder extends upwardly away from the body of the pump.
While the hooks are engaged with the second opening, the first and second openings of the one-piece occluder are retained in alignment relative to the aperture so that the third tube segment is not crimped, or occluded, by misalignment of the openings. Once the cover is oriented in the closed position, the exposed portion of the occluder is contacted by the cover and forced to bias inwardly upon itself such that the hooks are released from engagement with the second opening. After the hooks disengage the second opening, the one-piece occluder is maintained in an orientation with both first and second openings aligned relative to the aperture since the occluder is biased by the cover. However, if the cover happens to be disassociated from the housing the one-piece occluder automatically biases outwardly in order to misalign the first and second openings relative to the aperture, thereby occluding the tube assembly and prevent fluid flow therethrough.
Accordingly, the primary object of the present invention is to provide a one-piece unitary occluder adapted to prevent fluid-free flow in a fluid administration system having a pump which is connected in-line along a tube assembly.
Another object of the present invention is to provide an occluding device which minimizes the opportunity for mechanical failure during operation.
A further object of the present invention is to provide an occluding device that is inexpensive to manufacture.
These and other objects of the present invention are realized in the preferred embodiment of the present invention, described by way of example and not by way of limitation, which provides for a one-piece unitary occluder which is adapted to automatically occlude a portion of a tube assembly to prevent fluid free-flow whenever the tube assembly becomes disassociated from the pump.
Additional objects, advantages and novel features of the invention will be set forth in the description which follows, and will become apparent to those skilled in the art upon examination of the following more detailed description and drawings in which like elements of the invention are similarly numbered throughout.